6544640 has 36 divisors (see below), whose sum is σ = 15679524. Its totient is φ = 2617344.

The previous prime is 6544639. The next prime is 6544649. The reversal of 6544640 is 464456.

It can be written as a sum of positive squares in 2 ways, for example, as 861184 + 5683456 = 928^2 + 2384^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6544649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1277 + ... + 3836.

Almost surely, 2^6544640 is an apocalyptic number.

It is an amenable number.

6544640 is an abundant number, since it is smaller than the sum of its proper divisors (9134884).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6544640 is an equidigital number, since it uses as much as digits as its factorization.

6544640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5134 (or 5120 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 29.

The square root of 6544640 is about 2558.2494014462. The cubic root of 6544640 is about 187.0518124990.

The spelling of 6544640 in words is "six million, five hundred forty-four thousand, six hundred forty".